Previously an exclusive jersey for pros competing on the World Tour, the Castelli Men's Free AR 4. 1 Limited Edition Jersey saves approximately 12 watts at 40 kilometers per hour, compared to a traditional race-fit jersey. Seeing it's designed to shave split-seconds from competitive racing pursuits, you'll find the aero, race-specific cut hugs your body like a second skin. However, it's fabricated with a high degree of stretch, so you'll retain full range of motion and remain comfortable across long distances. Now that it's available for us mere mortals, Castelli updated it with all the bells and whistles to maximize functionality on everyday rides, including a rear-zip pocket for securing essentials on the road. The jersey itself is comprised of Velocity dimpled fabric along the front and shoulders to improve the aerodynamic efficiency, subsequently shaving precious time from your racing and training pursuits. Castelli didn't stop there with aero design details, going one step further by placing Nervato fabric along the armholes for a slippery, resistance-cutting effect.